Mulitple dr files with Full Backup

Is a specific dr file tied to a certain full backup? For example I do a full backup every day of the week. If it was Thursday and wanted to restore using Mondays tape, would the current dr file suffice or would I need the dr for that particular backup(monday)?

Yes. For all versions of BE, a .dr file is tied to a specific backup set. Although they share the same file name, they are not the same. The current .dr file will point to the latest backup set produced the job. The .dr file produced after the Monday backup will point to the Monday backup set and the .dr file produced after the Thursday backup will point to the Thursday backup set and so on. If you want to keep all versions of the .dr file, then you have to rename them to something else after they are produced, e.g. monday.dr, etc.